Abstract:

In this research, the changes of net photosynthetic rate of four Pumpkin cultivars were detected by automatic light quantum monitoring system at their vigorous growing stage (early flowering and setting fruit) in open field and solar greenhouse respectively, and the Photons were checked by quantometer at the same time. The pumpkin cultivars were used in our studies are as follows: Cucurbina moschata Duch.(Taijiuxiuli), C. mamxima Duch.(Yongan N0.2, giant pumpkin, NO.036, American mini pumpkin), C. pepo L.(Jingying NO.1), C. ficifolia Bouch(Yunnan black seed squash). The results showed that the diurnal variation of net photosynthetic rate of these four kinds of pumpkin were generally showed hyperbolic type, but were different in peak occurs time and peak values. The peak appeared around 15:30 in the afternoon, and the sub-peak appears in 9-11:30. The first peak of the C. pepo L. (Jingying NO.1) was the earliest to appear; the diurnal variation of transpiration rate E was also basically showed hyperbolic type, and there were some differences between the different cultivars, which C. moschata Duch.(Taijiuxiuli) has the highest water efficiency, while the black-seed squash was the lowest water efficiency.